1. Field of the Invention
The present invention relates to an image processing apparatus having a function of determining a specified original.
2. Related Background Arts
Various schemes have been devised to recognize specified originals.
A scheme for recognizing that the image pattern of an original is formed by a line drawing and a scheme for recognizing the color tone of an image original have also been proposed.
In addition, according to still another scheme, a specified original is also determined such that an infrared absorption ink is printed on the original, and an infrared ray is radiated on this original to detect the absorption rate.
When such a scheme is applied to, e.g., a copying machine, however, it is difficult to detect a specified original which forms an arbitrary angle with an arbitrary position on the original table of the copying machine. As a result, it is difficult to prevent a copying action of such an original.
Even if the line drawing information or the color tone of an original is detected, originals exhibiting the same characteristics as those of a specified original may be included in general originals. As a result, there is a possibility of erroneously determining a general original as a copy-prohibited original.
When infrared absorption of an original is detected, and image processing is performed as a result of the detection result, it is not determined whether an infrared absorbing material that is detected is a material purposely attached to indicate a specified original or accidentally attached to a general original, because a material (e.g., a green ink) for absorbing infrared rays may be present on general originals. There is a high possibility of erroneous determination.